The present disclosure relates generally to glass melting strategies and technologies, and more particularly, to an apparatus for treating molten glass exiting a submerged combustion melter that may be utilized before a finer.
Submerged combustion melting serves as an alternative to conventional glass melting. In submerged combustion melting, a mixture of fuel and oxidant is injected into the glass bath, resulting in combustion within the melt. Better melting rates than those typically found in conventional melters can be attained as a result of enhanced mixing and heat transfer in the bath.
One drawback of submerged combustion melting is that combustion gases are present within the melt as a result of submerged combustion. The large amount of gases in the melt, in conjunction with its agitated motion and interactions with the flame, can result in a glass melt that contains abundant gas bubbles having a wide distribution of sizes and quantities that can be orders of magnitude larger than those found in a conventional melter.
The dynamics of conventional submerged combustion processes can also result in a significantly perturbed melt free surface. Combustion gases expand and rise in the melt until they emerge at the free surface and leave the melter through the exhaust. One of the consequences of these perturbations is that the body of the melter is subjected to significant level of mechanical vibrations, which can be transmitted to the downstream processes. Also, these perturbations can create oscillations in the glass level that can translate into variations in the exiting glass flow rate.
These bubbles in the melt, vibrations of the melter, and variations in the exiting flow rate can constitute design challenges for glass fining steps downstream of the melter. The use of a conventional finer design attached to a submerged combustion melter is generally inadequate to solve the aforementioned design challenges. For example, a conventional finer would not be able to handle the excessive amount of gases in the melt or the associated foam that forms as gas bubbles rise to the glass free surface. Chemical fining can conventionally be used to address these issues; however, the effectiveness of chemical fining is limited since individual bubble growth while smaller, is more numerous creating foamy glass. Also, glass flow control can become much more difficult due to the two-phase nature of the foamy glass. As a consequence of these limitations, the use of submerged combustion melting has been constrained to applications with relatively low quality requirements (e.g., blister content).
When considering the use of submerged combustion melting for applications with high quality requirements, such as display and PV (photovoltaic) glasses, it is necessary to implement fining strategies that can address the large amount of gas bubbles and their wide size distribution. Thus, there is a need in the art for an improved submerged combustion melter and prefining mechanism.